A276126 a(0) = a(1) = a(2) = a(3) = a(4) = 1; for n>4, a(n) = ( a(n-1)^2+a(n-2)^2+a(n-3)^2+a(n-4)^2+a(n-1)*a(n-2)*a(n-3)*a(n-4) ) / a(n-5).

1, 1, 1, 1, 1, 5, 33, 1281, 1853441, 3826997739521, 2989151785658720873470945, 271581474754155314350055167823358355425497243141, 57581776430597685625970981157448022010386123824977761496513036956000541901241585948341716033

Offset

0,6

Links

Seiichi Manyama, Table of n, a(n) for n = 0..15

Formula

a(n) = 10*a(n-1)*a(n-2)*a(n-3)*a(n-4) - a(n-1)*a(n-2)*a(n-3) - a(n-2)*a(n-3)*a(n-4) - a(n-3)*a(n-4)*a(n-1) - a(n-4)*a(n-1)*a(n-2) - a(n-5).

Mathematica

nxt[{a_, b_, c_, d_, e_}]:={b, c, d, e, (e^2+d^2+c^2+b^2+e*d*c*b)/a}; NestList[nxt, {1, 1, 1, 1, 1}, 15][[All, 1]] (* Harvey P. Dale, Aug 08 2022 *)

Prog

(Ruby)
def A(m, n)
  a = Array.new(m, 1)
  ary = [1]
  while ary.size < n + 1
    i = a[1..-1].inject(0){|s, i| s + i * i} + a[1..-1].inject(:*)
    break if i % a[0] > 0
    a = *a[1..-1], i / a[0]
    ary << a[0]
  end
  ary
end
def A276126(n)
  A(5, n)
end

Crossrefs

Cf. A165903, A276124.

Sequence in context: A212296 A276160 A145505 * A193325 A303693 A256373

Adjacent sequences: A276123 A276124 A276125 * A276127 A276128 A276129

Keyword

nonn

Author

Seiichi Manyama, Aug 21 2016

Status

approved